1. Field of the Invention
The present invention relates to a stacked modular jack assembly, and particularly to a stacked LAN (Local Area Network) jack assembly having metal plate for shielding and grounding purposes.
2. Description of Related Art
It is quite common to use modular jacks for the data transmission in high speed applications such as IEEE 802.310Base-T or 100Base-T local area networks. A common problem to these high speed modular jacks is their tendency to emit high frequency radiation. There is also a need to provide means for suppressing undesirable noise.
Noise suppressors or signal conditioning components, such as common mode choke coils, are known in the art. The noise suppressors are mounted on a mother board on which the modular jack is seated. The noise suppressors are electrically connected with the modular jack by wires on the mother board. However, such signal conditioning components consume board real estate, which could otherwise be used for other circuitry. Furthermore, since the signal conditioning components are distant from the modular jack, the signal traces required to route the signals from the modular jack to the signal conditioning components degrade the signal integrity somewhat, thereby lowering the signal-to-noise ratio.
U.S. Pat. No. 5,069,641, issued to Sakanmoto et al, discloses a modular jack assembly comprising a dielectric housing and a printed circuit board disposed within the housing. The printed circuit board contains noise suppressors. A common mode choke coil and a three-terminal capacitor arrangement is used as a typical noise suppressor. The printed circuit board is fitted with contactors and terminals respectively for contacting with a modular plug and mounting the modular jack assembly on a mother board. The contactors and the terminals are electrically connected with the noise suppressors by wires on the printed circuit board.
U.S. Pat. Nos. 5,587,884 and 5,647,767, both assigned to The Whitaker Corporation, each disclose a modular jack assembly comprising an insulating housing and an insert subassembly received in the housing. The insert subassembly includes front and rear insert members. The front insert member has contact terminals encapsulated therein for mating with a modular plug. The rear insert member has a printed circuit board and leads encapsulated therein. The printed circuit board contains signal conditioning components such as common mode choke coils. The leads extend downwardly for electrically connecting to external circuits, such as a mother board. The terminals and the leads are soldered to the printed circuit board and electrically connected with the signal conditioning components by wires on the printed circuit board. Since the noise induced in the contact terminals of the modular jack assembly have similar spectral content, adequate cancellation of noise can be achieved by differential circuits. However, high speed applications such as 100 mbps local area networks require additional more sophisticated signal conditioning circuitry.
U.S. Pat. No. 5,687,233, assigned to Maxconn Incorporated, discloses a modular jack assembly addressing the problem encountered in the ""884 and ""767 patents. The modular jack assembly employs a number of signal conditioning components such as capacitors and magnetic coils to provide sufficient conditioning of data transmission. Signal pins are divided into a contact pin array and a mounting pin array. The two pin arrays are electrically coupled through an internal printed circuit board which has the capacitors and magnetic coils thereon. However, because the capacitors and magnetic coils are all mounted on the same printed circuit board, mutual interference between the signal conditioning components may also be a problem.
Recently, in order to save valuable real estate of mother boards in electronic devices, modular jacks are developed to be arranged in a stacked manner. Stewart, headquartered in Glen Rock, Pa., posted an article, entitled xe2x80x9cMagJack Family of Modular Jacks with Integrated Magneticsxe2x80x9d on the Internet website address, http://www.stewartconnector.com/pdfs/magjkfy.pdf. A modular jack introduced in this article has upper and lower ports. Two magnetic components needed for the upper and lower ports are housed within a jack body for protecting signals from internally and externally generated noise. However, because the two magnetic components are directly mounted in the jack body, crosstalk or EMI (Electromagnetic Interference) between the two magnetic components may become a serious problem.
Hence, a stacked jack assembly having improved electric capability is required to overcome the disadvantages of the prior art.
It is an object of the present invention to provide a stacked modular jack assembly having metal plate for preventing crosstalk between electronic components thereof.
It is another object of the present invention to provide a stacked modular jack assembly having metal plate for providing a grounding path for signal conditioning components thereof.
In order to achieve the objects set forth, an electrical connector assembly in accordance with the present invention comprises an insulating housing and an electrical subassembly disposed within the housing. The electrical subassembly includes first and second printed circuit boards each with contacts attached thereon, a pair of magnetic modules respectively connecting with the first and second contacts on the first and second printed circuit boards, and a metal plate having a plane body sandwiched between the pair of magnetic modules for shielding between the magnetic modules.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.